1. Field of the Invention
The present invention relates to a solar cell provided with a photoelectric conversion part as well as a plurality of finger electrodes formed on the photoelectric conversion part, and to a solar cell module provided with a plurality of solar cells, which are electrically connected to one another by wiring members, between a front surface protective member and a back surface protective member.
2. Description of the Related Art
Recently, in the field of solar cell modules, techniques to further improve the efficiency of the electric output per unit area have been vigorously developed.
A conventional solar cell module is provided with a plurality of solar cells, which are electrically connected to one another by wiring members, between a front surface protective member and a back surface protective member. The solar cell is provided with a photoelectric conversion part as well as a plurality of finger electrodes formed on the photoelectric conversion part. FIG. 1 is a top view of a conventional solar cell 10.
In general, an electric output of a solar cell module is proportional to a light-receiving area thereof. In other words, when the light-receiving area of the solar cell module becomes larger, a larger electric output can be obtained.
Accordingly, the electric output of the solar cell module can be made larger by setting a width of each of finger electrode 30 formed on a photoelectric conversion part 20 to be smaller, and by thus reducing areas that block incident light.
Here, linear expansion coefficient of materials for the photoelectric conversion part 20, that for, the finger electrode 30, and that for a wiring member 40 are different from one another. For this reason, stress occurs, between the materials, in an intersecting region α where the finger electrode 30 and the wiring member 40 intersect each other, due to temperature changes at the time when the wiring member 40 is soldered on the solar cell 10. In addition, such stress may also occur, between the materials, due to temperature changes in an actual use environment.
Thus, when a width of the finger electrode 30 is made smaller to increase the electric output of the solar cell module, the possibility of causing disconnection of the finger electrode 30 becomes higher due to the stress in the intersecting region α. FIG. 2A is an enlarged view of portion A in FIG. 1.
In order to avoid the disconnection of the finger electrode 30, as shown in FIGS. 2B and 2C, it is possible that the finger electrode 30 is made wider at a root portion of the intersecting region α (for example, see Japanese Patent Application Laid-open Publication No. 2003-338631).